This invention relates to dynamoelectric machines and more particularly to homopolar dynamoelectric machines.
A homopolar dynamoelectric machine, when used as a generator, supplies D.C. current directly from a conductor in relative motion with respect to lines of magnetic flux and cutting such magnetic flux during that motion. That is because the polarity of the magnetic flux cut by such a surface, relative to the direction of motion of the surface with respect to the magnetic flux, does not change at any time during operation of the generator. In contrast, conventional generators based on relative motion between a magnetic field and a conductor generate D.C. current by first generating A.C. current and then converting it to D.C. current. Homopolar electrical generators more efficiently generate a larger D.C. output current than conventional generators based on D.C. output current than conventional generators based on relative motion between a conductor and a magnetic field. U.S. Pat. No. 4,710,665 naming the applicant as an inventor contains a general description of drum-type homopolar dynamoelectric machines.
Though the concept of homopolar dynamoelectric machines has been known for a long time, there has not been much activity in its further research and development. For instance, although it has been known since the last century to use multiple coils or segments of a single coil to supply plural outputs from a single A.C. to D.C. conversion type generator, no homopolar dynamoelectric machine known by the applicant has embodied the feature of having multiple output terminals independently supplying a separate output.
At least in one area of application of generators--the testing of electromagnetic gun configurations--the requirement for current is high. For that reason, homopolar generators are especially suitable for that application. However, in that application, the required current, voltage, and energy may vary quite often. The cost of having a separate generator for each different output requirement is high.
It has been known in the past to skew the current path within a none..rotating part of a homopolar dynamoelectric machine to create magnetic flux which adds to the flux originally generated by the machine to increase its efficiency. The previously mentioned U.S. Pat. No. 4,710,665 discloses one such machine. Skewing formed on a surface area generally weakens it. Because a rotating conductor may rotate at high speeds, the weakened surface area may become damaged when subjected to high centrifugal force during rotation. A stator conductor does not rotate and thus does not have this problem if its surface is skewed.